ARMBaseInstrInfo.h revision cd81d94322a39503e4a3e87b6ee03d4fcb3465fb 
1//===-- ARMBaseInstrInfo.h - ARM Base Instruction Information ---*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file contains the Base ARM implementation of the TargetInstrInfo class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef ARMBASEINSTRUCTIONINFO_H
15#define ARMBASEINSTRUCTIONINFO_H
16
17#include "MCTargetDesc/ARMBaseInfo.h"
18#include "llvm/ADT/DenseMap.h"
19#include "llvm/ADT/SmallSet.h"
20#include "llvm/CodeGen/MachineInstrBuilder.h"
21#include "llvm/Target/TargetInstrInfo.h"
22
23#define GET_INSTRINFO_HEADER
24#include "ARMGenInstrInfo.inc"
25
26namespace llvm {
27  class ARMSubtarget;
28  class ARMBaseRegisterInfo;
29
30class ARMBaseInstrInfo : public ARMGenInstrInfo {
31  const ARMSubtarget &Subtarget;
32
33protected:
34  // Can be only subclassed.
35  explicit ARMBaseInstrInfo(const ARMSubtarget &STI);
36
37public:
38  // Return whether the target has an explicit NOP encoding.
39  bool hasNOP() const;
40
41  // Return the non-pre/post incrementing version of 'Opc'. Return 0
42  // if there is not such an opcode.
43  virtual unsigned getUnindexedOpcode(unsigned Opc) const =0;
44
45  MachineInstr *convertToThreeAddress(MachineFunction::iterator &MFI,
46                                      MachineBasicBlock::iterator &MBBI,
47                                      LiveVariables *LV) const override;
48
49  virtual const ARMBaseRegisterInfo &getRegisterInfo() const = 0;
50  const ARMSubtarget &getSubtarget() const { return Subtarget; }
51
52  ScheduleHazardRecognizer *
53  CreateTargetHazardRecognizer(const TargetSubtargetInfo *STI,
54                               const ScheduleDAG *DAG) const override;
55
56  ScheduleHazardRecognizer *
57  CreateTargetPostRAHazardRecognizer(const InstrItineraryData *II,
58                                     const ScheduleDAG *DAG) const override;
59
60  // Branch analysis.
61  bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
62                     MachineBasicBlock *&FBB,
63                     SmallVectorImpl<MachineOperand> &Cond,
64                     bool AllowModify = false) const override;
65  unsigned RemoveBranch(MachineBasicBlock &MBB) const override;
66  unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
67                        MachineBasicBlock *FBB,
68                        const SmallVectorImpl<MachineOperand> &Cond,
69                        DebugLoc DL) const override;
70
71  bool
72  ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;
73
74  // Predication support.
75  bool isPredicated(const MachineInstr *MI) const override;
76
77  ARMCC::CondCodes getPredicate(const MachineInstr *MI) const {
78    int PIdx = MI->findFirstPredOperandIdx();
79    return PIdx != -1 ? (ARMCC::CondCodes)MI->getOperand(PIdx).getImm()
80                      : ARMCC::AL;
81  }
82
83  bool PredicateInstruction(MachineInstr *MI,
84                    const SmallVectorImpl<MachineOperand> &Pred) const override;
85
86  bool SubsumesPredicate(const SmallVectorImpl<MachineOperand> &Pred1,
87                   const SmallVectorImpl<MachineOperand> &Pred2) const override;
88
89  bool DefinesPredicate(MachineInstr *MI,
90                        std::vector<MachineOperand> &Pred) const override;
91
92  bool isPredicable(MachineInstr *MI) const override;
93
94  /// GetInstSize - Returns the size of the specified MachineInstr.
95  ///
96  virtual unsigned GetInstSizeInBytes(const MachineInstr* MI) const;
97
98  unsigned isLoadFromStackSlot(const MachineInstr *MI,
99                               int &FrameIndex) const override;
100  unsigned isStoreToStackSlot(const MachineInstr *MI,
101                              int &FrameIndex) const override;
102  unsigned isLoadFromStackSlotPostFE(const MachineInstr *MI,
103                                     int &FrameIndex) const override;
104  unsigned isStoreToStackSlotPostFE(const MachineInstr *MI,
105                                    int &FrameIndex) const override;
106
107  void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
108                   DebugLoc DL, unsigned DestReg, unsigned SrcReg,
109                   bool KillSrc) const override;
110
111  void storeRegToStackSlot(MachineBasicBlock &MBB,
112                           MachineBasicBlock::iterator MBBI,
113                           unsigned SrcReg, bool isKill, int FrameIndex,
114                           const TargetRegisterClass *RC,
115                           const TargetRegisterInfo *TRI) const override;
116
117  void loadRegFromStackSlot(MachineBasicBlock &MBB,
118                            MachineBasicBlock::iterator MBBI,
119                            unsigned DestReg, int FrameIndex,
120                            const TargetRegisterClass *RC,
121                            const TargetRegisterInfo *TRI) const override;
122
123  bool expandPostRAPseudo(MachineBasicBlock::iterator MI) const override;
124
125  void reMaterialize(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
126                     unsigned DestReg, unsigned SubIdx,
127                     const MachineInstr *Orig,
128                     const TargetRegisterInfo &TRI) const override;
129
130  MachineInstr *duplicate(MachineInstr *Orig,
131                          MachineFunction &MF) const override;
132
133  MachineInstr *commuteInstruction(MachineInstr*,
134                                   bool=false) const override;
135
136  const MachineInstrBuilder &AddDReg(MachineInstrBuilder &MIB, unsigned Reg,
137                                     unsigned SubIdx, unsigned State,
138                                     const TargetRegisterInfo *TRI) const;
139
140  bool produceSameValue(const MachineInstr *MI0, const MachineInstr *MI1,
141                        const MachineRegisterInfo *MRI) const override;
142
143  /// areLoadsFromSameBasePtr - This is used by the pre-regalloc scheduler to
144  /// determine if two loads are loading from the same base address. It should
145  /// only return true if the base pointers are the same and the only
146  /// differences between the two addresses is the offset. It also returns the
147  /// offsets by reference.
148  bool areLoadsFromSameBasePtr(SDNode *Load1, SDNode *Load2, int64_t &Offset1,
149                               int64_t &Offset2) const override;
150
151  /// shouldScheduleLoadsNear - This is a used by the pre-regalloc scheduler to
152  /// determine (in conjunction with areLoadsFromSameBasePtr) if two loads
153  /// should be scheduled togther. On some targets if two loads are loading from
154  /// addresses in the same cache line, it's better if they are scheduled
155  /// together. This function takes two integers that represent the load offsets
156  /// from the common base address. It returns true if it decides it's desirable
157  /// to schedule the two loads together. "NumLoads" is the number of loads that
158  /// have already been scheduled after Load1.
159  bool shouldScheduleLoadsNear(SDNode *Load1, SDNode *Load2,
160                               int64_t Offset1, int64_t Offset2,
161                               unsigned NumLoads) const override;
162
163  bool isSchedulingBoundary(const MachineInstr *MI,
164                            const MachineBasicBlock *MBB,
165                            const MachineFunction &MF) const override;
166
167  bool isProfitableToIfCvt(MachineBasicBlock &MBB,
168                           unsigned NumCycles, unsigned ExtraPredCycles,
169                           const BranchProbability &Probability) const override;
170
171  bool isProfitableToIfCvt(MachineBasicBlock &TMBB, unsigned NumT,
172                           unsigned ExtraT, MachineBasicBlock &FMBB,
173                           unsigned NumF, unsigned ExtraF,
174                           const BranchProbability &Probability) const override;
175
176  bool isProfitableToDupForIfCvt(MachineBasicBlock &MBB, unsigned NumCycles,
177                          const BranchProbability &Probability) const override {
178    return NumCycles == 1;
179  }
180
181  bool isProfitableToUnpredicate(MachineBasicBlock &TMBB,
182                                 MachineBasicBlock &FMBB) const override;
183
184  /// analyzeCompare - For a comparison instruction, return the source registers
185  /// in SrcReg and SrcReg2 if having two register operands, and the value it
186  /// compares against in CmpValue. Return true if the comparison instruction
187  /// can be analyzed.
188  bool analyzeCompare(const MachineInstr *MI, unsigned &SrcReg,
189                      unsigned &SrcReg2, int &CmpMask,
190                      int &CmpValue) const override;
191
192  /// optimizeCompareInstr - Convert the instruction to set the zero flag so
193  /// that we can remove a "comparison with zero"; Remove a redundant CMP
194  /// instruction if the flags can be updated in the same way by an earlier
195  /// instruction such as SUB.
196  bool optimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg,
197                            unsigned SrcReg2, int CmpMask, int CmpValue,
198                            const MachineRegisterInfo *MRI) const override;
199
200  bool analyzeSelect(const MachineInstr *MI,
201                     SmallVectorImpl<MachineOperand> &Cond,
202                     unsigned &TrueOp, unsigned &FalseOp,
203                     bool &Optimizable) const override;
204
205  MachineInstr *optimizeSelect(MachineInstr *MI, bool) const override;
206
207  /// FoldImmediate - 'Reg' is known to be defined by a move immediate
208  /// instruction, try to fold the immediate into the use instruction.
209  bool FoldImmediate(MachineInstr *UseMI, MachineInstr *DefMI,
210                     unsigned Reg, MachineRegisterInfo *MRI) const override;
211
212  unsigned getNumMicroOps(const InstrItineraryData *ItinData,
213                          const MachineInstr *MI) const override;
214
215  int getOperandLatency(const InstrItineraryData *ItinData,
216                        const MachineInstr *DefMI, unsigned DefIdx,
217                        const MachineInstr *UseMI,
218                        unsigned UseIdx) const override;
219  int getOperandLatency(const InstrItineraryData *ItinData,
220                        SDNode *DefNode, unsigned DefIdx,
221                        SDNode *UseNode, unsigned UseIdx) const override;
222
223  /// VFP/NEON execution domains.
224  std::pair<uint16_t, uint16_t>
225  getExecutionDomain(const MachineInstr *MI) const override;
226  void setExecutionDomain(MachineInstr *MI, unsigned Domain) const override;
227
228  unsigned getPartialRegUpdateClearance(const MachineInstr*, unsigned,
229                                      const TargetRegisterInfo*) const override;
230  void breakPartialRegDependency(MachineBasicBlock::iterator, unsigned,
231                                 const TargetRegisterInfo *TRI) const override;
232
233  void
234  getUnconditionalBranch(MCInst &Branch,
235                         const MCSymbolRefExpr *BranchTarget) const override;
236
237  void getTrap(MCInst &MI) const override;
238
239  /// Get the number of addresses by LDM or VLDM or zero for unknown.
240  unsigned getNumLDMAddresses(const MachineInstr *MI) const;
241
242private:
243  unsigned getInstBundleLength(const MachineInstr *MI) const;
244
245  int getVLDMDefCycle(const InstrItineraryData *ItinData,
246                      const MCInstrDesc &DefMCID,
247                      unsigned DefClass,
248                      unsigned DefIdx, unsigned DefAlign) const;
249  int getLDMDefCycle(const InstrItineraryData *ItinData,
250                     const MCInstrDesc &DefMCID,
251                     unsigned DefClass,
252                     unsigned DefIdx, unsigned DefAlign) const;
253  int getVSTMUseCycle(const InstrItineraryData *ItinData,
254                      const MCInstrDesc &UseMCID,
255                      unsigned UseClass,
256                      unsigned UseIdx, unsigned UseAlign) const;
257  int getSTMUseCycle(const InstrItineraryData *ItinData,
258                     const MCInstrDesc &UseMCID,
259                     unsigned UseClass,
260                     unsigned UseIdx, unsigned UseAlign) const;
261  int getOperandLatency(const InstrItineraryData *ItinData,
262                        const MCInstrDesc &DefMCID,
263                        unsigned DefIdx, unsigned DefAlign,
264                        const MCInstrDesc &UseMCID,
265                        unsigned UseIdx, unsigned UseAlign) const;
266
267  unsigned getPredicationCost(const MachineInstr *MI) const override;
268
269  unsigned getInstrLatency(const InstrItineraryData *ItinData,
270                           const MachineInstr *MI,
271                           unsigned *PredCost = nullptr) const override;
272
273  int getInstrLatency(const InstrItineraryData *ItinData,
274                      SDNode *Node) const override;
275
276  bool hasHighOperandLatency(const InstrItineraryData *ItinData,
277                             const MachineRegisterInfo *MRI,
278                             const MachineInstr *DefMI, unsigned DefIdx,
279                             const MachineInstr *UseMI,
280                             unsigned UseIdx) const override;
281  bool hasLowDefLatency(const InstrItineraryData *ItinData,
282                        const MachineInstr *DefMI,
283                        unsigned DefIdx) const override;
284
285  /// verifyInstruction - Perform target specific instruction verification.
286  bool verifyInstruction(const MachineInstr *MI,
287                         StringRef &ErrInfo) const override;
288
289private:
290  /// Modeling special VFP / NEON fp MLA / MLS hazards.
291
292  /// MLxEntryMap - Map fp MLA / MLS to the corresponding entry in the internal
293  /// MLx table.
294  DenseMap<unsigned, unsigned> MLxEntryMap;
295
296  /// MLxHazardOpcodes - Set of add / sub and multiply opcodes that would cause
297  /// stalls when scheduled together with fp MLA / MLS opcodes.
298  SmallSet<unsigned, 16> MLxHazardOpcodes;
299
300public:
301  /// isFpMLxInstruction - Return true if the specified opcode is a fp MLA / MLS
302  /// instruction.
303  bool isFpMLxInstruction(unsigned Opcode) const {
304    return MLxEntryMap.count(Opcode);
305  }
306
307  /// isFpMLxInstruction - This version also returns the multiply opcode and the
308  /// addition / subtraction opcode to expand to. Return true for 'HasLane' for
309  /// the MLX instructions with an extra lane operand.
310  bool isFpMLxInstruction(unsigned Opcode, unsigned &MulOpc,
311                          unsigned &AddSubOpc, bool &NegAcc,
312                          bool &HasLane) const;
313
314  /// canCauseFpMLxStall - Return true if an instruction of the specified opcode
315  /// will cause stalls when scheduled after (within 4-cycle window) a fp
316  /// MLA / MLS instruction.
317  bool canCauseFpMLxStall(unsigned Opcode) const {
318    return MLxHazardOpcodes.count(Opcode);
319  }
320
321  /// Returns true if the instruction has a shift by immediate that can be
322  /// executed in one cycle less.
323  bool isSwiftFastImmShift(const MachineInstr *MI) const;
324};
325
326static inline
327const MachineInstrBuilder &AddDefaultPred(const MachineInstrBuilder &MIB) {
328  return MIB.addImm((int64_t)ARMCC::AL).addReg(0);
329}
330
331static inline
332const MachineInstrBuilder &AddDefaultCC(const MachineInstrBuilder &MIB) {
333  return MIB.addReg(0);
334}
335
336static inline
337const MachineInstrBuilder &AddDefaultT1CC(const MachineInstrBuilder &MIB,
338                                          bool isDead = false) {
339  return MIB.addReg(ARM::CPSR, getDefRegState(true) | getDeadRegState(isDead));
340}
341
342static inline
343const MachineInstrBuilder &AddNoT1CC(const MachineInstrBuilder &MIB) {
344  return MIB.addReg(0);
345}
346
347static inline
348bool isUncondBranchOpcode(int Opc) {
349  return Opc == ARM::B || Opc == ARM::tB || Opc == ARM::t2B;
350}
351
352static inline
353bool isCondBranchOpcode(int Opc) {
354  return Opc == ARM::Bcc || Opc == ARM::tBcc || Opc == ARM::t2Bcc;
355}
356
357static inline
358bool isJumpTableBranchOpcode(int Opc) {
359  return Opc == ARM::BR_JTr || Opc == ARM::BR_JTm || Opc == ARM::BR_JTadd ||
360    Opc == ARM::tBR_JTr || Opc == ARM::t2BR_JT;
361}
362
363static inline
364bool isIndirectBranchOpcode(int Opc) {
365  return Opc == ARM::BX || Opc == ARM::MOVPCRX || Opc == ARM::tBRIND;
366}
367
368static inline bool isPopOpcode(int Opc) {
369  return Opc == ARM::tPOP_RET || Opc == ARM::LDMIA_RET ||
370         Opc == ARM::t2LDMIA_RET || Opc == ARM::tPOP || Opc == ARM::LDMIA_UPD ||
371         Opc == ARM::t2LDMIA_UPD || Opc == ARM::VLDMDIA_UPD;
372}
373
374static inline bool isPushOpcode(int Opc) {
375  return Opc == ARM::tPUSH || Opc == ARM::t2STMDB_UPD ||
376         Opc == ARM::STMDB_UPD || Opc == ARM::VSTMDDB_UPD;
377}
378
379/// getInstrPredicate - If instruction is predicated, returns its predicate
380/// condition, otherwise returns AL. It also returns the condition code
381/// register by reference.
382ARMCC::CondCodes getInstrPredicate(const MachineInstr *MI, unsigned &PredReg);
383
384int getMatchingCondBranchOpcode(int Opc);
385
386/// Determine if MI can be folded into an ARM MOVCC instruction, and return the
387/// opcode of the SSA instruction representing the conditional MI.
388unsigned canFoldARMInstrIntoMOVCC(unsigned Reg,
389                                  MachineInstr *&MI,
390                                  const MachineRegisterInfo &MRI);
391
392/// Map pseudo instructions that imply an 'S' bit onto real opcodes. Whether
393/// the instruction is encoded with an 'S' bit is determined by the optional
394/// CPSR def operand.
395unsigned convertAddSubFlagsOpcode(unsigned OldOpc);
396
397/// emitARMRegPlusImmediate / emitT2RegPlusImmediate - Emits a series of
398/// instructions to materializea destreg = basereg + immediate in ARM / Thumb2
399/// code.
400void emitARMRegPlusImmediate(MachineBasicBlock &MBB,
401                             MachineBasicBlock::iterator &MBBI, DebugLoc dl,
402                             unsigned DestReg, unsigned BaseReg, int NumBytes,
403                             ARMCC::CondCodes Pred, unsigned PredReg,
404                             const ARMBaseInstrInfo &TII, unsigned MIFlags = 0);
405
406void emitT2RegPlusImmediate(MachineBasicBlock &MBB,
407                            MachineBasicBlock::iterator &MBBI, DebugLoc dl,
408                            unsigned DestReg, unsigned BaseReg, int NumBytes,
409                            ARMCC::CondCodes Pred, unsigned PredReg,
410                            const ARMBaseInstrInfo &TII, unsigned MIFlags = 0);
411void emitThumbRegPlusImmediate(MachineBasicBlock &MBB,
412                               MachineBasicBlock::iterator &MBBI, DebugLoc dl,
413                               unsigned DestReg, unsigned BaseReg,
414                               int NumBytes, const TargetInstrInfo &TII,
415                               const ARMBaseRegisterInfo& MRI,
416                               unsigned MIFlags = 0);
417
418/// Tries to add registers to the reglist of a given base-updating
419/// push/pop instruction to adjust the stack by an additional
420/// NumBytes. This can save a few bytes per function in code-size, but
421/// obviously generates more memory traffic. As such, it only takes
422/// effect in functions being optimised for size.
423bool tryFoldSPUpdateIntoPushPop(const ARMSubtarget &Subtarget,
424                                MachineFunction &MF, MachineInstr *MI,
425                                unsigned NumBytes);
426
427/// rewriteARMFrameIndex / rewriteT2FrameIndex -
428/// Rewrite MI to access 'Offset' bytes from the FP. Return false if the
429/// offset could not be handled directly in MI, and return the left-over
430/// portion by reference.
431bool rewriteARMFrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
432                          unsigned FrameReg, int &Offset,
433                          const ARMBaseInstrInfo &TII);
434
435bool rewriteT2FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
436                         unsigned FrameReg, int &Offset,
437                         const ARMBaseInstrInfo &TII);
438
439} // End llvm namespace
440
441#endif
442